[drizzit1aa]

I am having one hell of a time with these parts. All outside corner welds, bends are bad so there are gaps in places (can't be helped). I have my Miller TIG Runner 400 set at 20 amps, 2.0 PPS, 3/32" 2% Lanthinated, using FLEX-LOC 250 WATER COOLED TORCH with an #8 cup and a CK gas saver with an #18 cup. I have tried wrapping the boxes with aluminum foil to purge, chill plates top and bottom of seams to be welded.

The edges that are touching not much of a problem, silver all the way some straw. It's when I get to the openings and try to add filler, nasty and busting through to the inside of the boxes way too much for my tastes and it will be the customers also.

Any suggestions?

[Oscar]

We can't see what you're working with. How bad are the gaps? Are you backpurging?

[cj737]

One trick I use when welding outside corners on stainless is to clamp Aluminum angle iron on the inside. This acts as a chill block, a backstop for the argon, and holds the corner joint in place during welding.

18ga stainless will be daunting on corners no matter what you do. If the weld is good with no filler, but blows out with filler, your amps are too low. When you introduce filler you need to run more heat to melt that extra material. Likely you are loitering over the spot trying to get the filler to melt, which in turn heat soaks the base metal. And without an active back purge, sugar!

SolarFlux paste is also useful to apply to inside when an active purge is unavailable. Helps a lot to eliminate the sugaring.

[drizzit1aa]

I have never heard of SolarFlux. Thanks, I'll check on it. .... Aaaaand just read up on it. It's said that it's hard to clean off afterwards. Is it going to be baked on?

[Oscar]

Yea it's pretty tough to remove. It's not like stick welding slag where it can be relatively easily chipped off.

[tweake]

I am having one hell of a time with these parts. All outside corner welds, bends are bad so there are gaps in places (can't be helped). I have my Miller TIG Runner 400 set at 20 amps, 2.0 PPS, 3/32" 2% Lanthinated, using FLEX-LOC 250 WATER COOLED TORCH with an #8 cup and a CK gas saver with an #18 cup. I have tried wrapping the boxes with aluminum foil to purge, chill plates top and bottom of seams to be welded.

The edges that are touching not much of a problem, silver all the way some straw. It's when I get to the openings and try to add filler, nasty and busting through to the inside of the boxes way too much for my tastes and it will be the customers also.

Any suggestions?

what size material is it made from and what size and type of filler are you using?

does your machine have pulse?

i find openings on thin material is a right pain unless you have a welded bit to start from. ie where its touching weld that then add filler to the end of that. depending on width you may have to do a bit of a weave, or even a circle, to widen up the weld area otherwise you will melt back the edge.
it can be a bit of mix of styles between welding and brazing. add filler wash it into place. sometimes i will do circles (like mig) so you get more of a melt and freeze motion.

this is why i'm trying to get better fit ups, it makes the welding so much easier.

[drizzit1aa]

I have my Miller TIG Runner 400 set at 20 amps, 2.0 PPS, 3/32" 2% Lanthinated, using FLEX-LOC 250 WATER COOLED TORCH with an #8 cup and a CK gas saver with an #18 cup.

308L, .035 filler, 18 gauge stainless, base unknown stainless

For some reason my phone isn't sending pictures to my email so I can't get any pics. of the job.

[tweake]

I have my Miller TIG Runner 400 set at 20 amps, 2.0 PPS, 3/32" 2% Lanthinated, using FLEX-LOC 250 WATER COOLED TORCH with an #8 cup and a CK gas saver with an #18 cup.

308L, .035 filler, 18 gauge stainless, base unknown stainless

For some reason my phone isn't sending pictures to my email so I can't get any pics. of the job.

i would go bigger filler. melt then chill. rough rule of thumb filler the same size parent.

[raticus]

I spent several years working in a sheet metal shop where the majority of what we did was thin stainless sheet (lots of kitchen stuff)... I guess this is a moot point as you're asking how to work with gaps in your work, that you have no choice, but yeah... why on earth are there gaps? That's a big no no on thin anything, not just stainless. Anyway, I guess that's out of your control... The one thing I learned about welding thin stainless corners, is hot and fast. Yeah, doesn't seem logical but it works. Don't drop your amps, crank it up, and don't weld slow, move quick... Don't need any special anything, just stainless filler of any kind, and not too small (we used to cut our own filler by putting the big hydraulic shear on auto, ramping up the speed and cutting a huge batch of homemade filler from the same sheet we were welding with... you get real good at it after awhile, getting just the right size you want.. makes a hell of a racket though lol)... 3/32 or 1/6th, just not any smaller (I always preferred 3/32). Also, always have an aluminum backing, and not foil... a nice thick piece of aluminum, the thicker the better. Clamp it on tight, and weld hot and fast. Now if you're doing butt welding of thin stainless, it's a lot tougher. The trick there is not only big aluminum heat sinks behind it (btw, you don't need any kind of back purge on anything other than say, tubing... as the aluminum plate you've clamped on the back will keep any oxygen from messing your weld up back there)... but using wet rags. Yeah, it's a bit of a pain, as you risk getting water in your weld area, but it works. The key is to do it a lot, use a very wet rag but not too soaked where you end up squeezing out a ton of water on everything. Weld a short bead, stop, grab the rag that's soaking in a pot next to you and soak the area around it... then repeat... Weld, soak, dry.. weld, soak, dry. Sometimes I'd use an air gun to blow the excess out of the way if I used too much water. You just can't weld any more than a short bead at a time, or it'll warp and all the water in the world won't help. Also, a pulsed inverter makes it a lot easier, but not really needed... I used an old box that had no pulse or anything fancy and you just gotta pay attention and get wet! But yeah, back to your corner welds... hot and fast!

[drizzit1aa]

Bit late, but here is what I ended up doing.